Temperature Dependence of the Co Hyperfine Field in

Abstract

To understand more fully the magnetic structure of GdCo2 we have investigated the field and temperature dependence of the Co hyperfine field in this cubic‐Laves phase ferrimagnet. The hyperfine field at Co nuclei is 61.3 kOe at 1.4 K and the sign of this field is positive with respect to the sample magnetization. Below 200 K the Co resonance is basically a single line. Above this temperature, near which a pronounced inflection appears in the saturation magnetization vs. temperature curve, the Co spectrum becomes complex. Above 260 K it is composed of two closely spaced but resolved lines. The temperature dependence of the sublattice magnetizations are analyzed in the light of the bulk magnetization behavior and this hyperfine field data. The significance of the spectral structure and the temperature dependence of the Co sublattice magnetization are explored within the context of existing models of the magnetic structure.